simple problem, need help fast

Thread Starter


Joined Oct 4, 2013
hello, my wive broke the traces off the tiny micro-usb charger plug on her phone. so I had a small piece of 5 line flat ribbon cable that I can connect to the battery under the case and still put the cover on, Ive got it set up so the cable folds inside the batt. cover until its needed , then it comes out about 4 inches, and I have a socket the ribbon plubs in. Ive soldered the socket a piece of protoboard and ive used a length of usb wire with a usb plug on one end and the red and black wire on the other. now I could connect the usb wire to the pins on the ribbon socket and charge the phone, but I wanted to know how hard it would be to add a red LED showing the charger has power and a green one that shows charging when its plugged into the phone. I need to have this finished tonite, so somw quick replies would be just awesome... Oh, and should I add a cap there to keep the current smooth?


Joined Sep 9, 2010
Power-on indication is easy - just use a red LED across the power pins with the appropriate resistor. I haven't done the calculation but it will be something like 200Ω.

A phone-connected indicator is trickier. I can think of several ways but none without other components (a comparator). Maybe someone else has a simpler idea.


Joined Nov 24, 2012
I wouldn't do it, get the phone fixed or get another phone. The charging circuit that keeps you from overcharging the battery is in the phone. If you bypass the charging circuit you stand a big chance of overcharging the battery and causing a fire. Lipo's do not like to be overcharged.

If it's not a popular $mart phone. I have had real good luck finding phones on eBay for less than I could get one repaired. Most often can find the exact phone for a few bucks. Stick the SIM card out of your old phone in the eBay phone and you are back in business.